The use of herbal extracts for treatment of benign prostatic hyperplasia (BPH) is growing rapidly in the United States. Numerous small clinical studies, carried out primarily in Europe, suggest that some of these extracts have great potential for providing relief of symptoms and, possibly, altering the natural course of BPH. The size and quality of prior studies, however, make it impossible to provide firm evidence-based recommendations to patients;the need for higher-quality, longer-term studies is compelling. This proposal describes plans to establish a Clinical Evaluation and Treatment Center in response to RFA # DK-02-026. We plan to bring the substantial patient population and scientific resources of the Northern California Kaiser-Permanente (NCKP) Division of Research (DOR) to support the successful completion of this important multicenter randomized clinical trial. While the final details of the research protocol will be established by the trial's Steering and Planning Committee, the approach described in this proposal is based on prior successful trials of BPH therapeutics and an ongoing NIH-funded randomized, double-blind, placebo-controlled trial of saw palmetto currently being conducted by our group. Participants will be recruited from five NCKP clinical facilities, which serve over 100,000 men aged 50 and older who are unlikely to meet exclusion criteria. Entry criteria include male participants at least 50 years old with an American Urological Association Symptom Index (AUASI) Score >7, no prior history of prostate cancer or prostate surgery, PSA below the age-adjusted upper limit (or PSA<10 with negative prostate biopsy), and creatinine<2.0mg/dl. Patients on current medical therapy will undergo a wash-out phase prior to final eligibility determination. Eligible patients will undergo a one-month single-blind run-in period;those demonstrating adequate adherence will be randomized in equal proportions to saw palmetto, pygeum, or placebo. Patients will be followed at four-month intervals for a period of four-to-six years. Primary endpoints are those specified in the RFA (acute urinary retention, BPH-related renal insufficiency, recurrent urinary tract infections, incontinence, and an increase of at least 4 points in the AUASI);secondary endpoints include symptom scores, uroflow measurements, and adverse effects. A systematic, multifaceted approach will be used to promote participant adherence to the study protocol.